Field of Invention
The present invention relates to an electromagnetic induction type position detector.
Background Art
An electromagnetic induction type position detector is applied to position detection in various machines such as a machine tool, an automobile, a robot, and the like, and there are a linear type scale and a rotary type scale. The linear type scale is installed on a moving body such as a table of a machine tool to detect a linear moving position of the moving body, and the rotary type scale is installed on a moving body (a rotating body) such as a rotary table of a machine tool to detect a rotational position (a rotational angle) of the moving body.
The linear type scale and the rotary type scale detect a position by electromagnetic induction of patterns disposed so as to face each other in parallel to each other. The linear type scale has a slider which is a primary-side member and a scale which is a secondary-side member. The detection principle of the rotary type scale is also the same as that of the linear type scale, and a stator and a rotor of the rotary type scale respectively correspond to the slider and the scale of the linear type scale.
In the related art of a linear type scale described in PTL 1 described below, if an excitation signal is provided from an excitation signal generator to a transmission winding in a slider, an eddy current is generated in a flux modulation unit in a scale, and as a result, an induced voltage is generated in a reception winding in the slider. Then, the position of the slider can be detected based on a change of the voltage.